From ab20ea1d78697aa88dd84b8be4ac385cf295ea20 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Caol=C3=A1n=20McNamara?= <caolanm@redhat.com>
Date: Tue, 8 Dec 2015 15:52:47 +0000
Subject: [PATCH] Resolves: rhbz#1289398 unable to use scroll wheel under
 wayland

because we only get smooth scroll events, so implement that as
best we can.

(cherry picked from commit c5c1f8f710760d40ca1004c5fdd69f8fa2c87496)

Change-Id: I7701949cf7c9ffdc9d062f75b23db7c6add3c6a9
---
 vcl/inc/unx/gtk/gtkframe.hxx       |  1 +
 vcl/unx/gtk/window/gtksalframe.cxx | 70 +++++++++++++++++++++++++++-----------
 2 files changed, 52 insertions(+), 19 deletions(-)

diff --git a/vcl/inc/unx/gtk/gtkframe.hxx b/vcl/inc/unx/gtk/gtkframe.hxx
index 3531c41..4594249 100644
--- a/vcl/inc/unx/gtk/gtkframe.hxx
+++ b/vcl/inc/unx/gtk/gtkframe.hxx
@@ -211,6 +211,7 @@ class GtkSalFrame : public SalFrame, public X11WindowProvider
     Rectangle                       m_aRestorePosSize;
 
 #if GTK_CHECK_VERSION(3,0,0)
+    guint32                         m_nLastScrollEventTime;
     cairo_region_t*                 m_pRegion;
 #else
     GdkRegion*                      m_pRegion;
diff --git a/vcl/unx/gtk/window/gtksalframe.cxx b/vcl/unx/gtk/window/gtksalframe.cxx
index 614974a..616f73f 100644
--- a/vcl/unx/gtk/window/gtksalframe.cxx
+++ b/vcl/unx/gtk/window/gtksalframe.cxx
@@ -1129,6 +1129,9 @@ void GtkSalFrame::InitCommon()
     m_bSpanMonitorsWhenFullscreen = false;
     m_nState            = GDK_WINDOW_STATE_WITHDRAWN;
     m_nVisibility       = GDK_VISIBILITY_FULLY_OBSCURED;
+#if GTK_CHECK_VERSION(3,0,0)
+    m_nLastScrollEventTime = GDK_CURRENT_TIME;
+#endif
     m_bSendModChangeOnRelease = false;
     m_pIMHandler        = NULL;
     m_hBackgroundPixmap = None;
@@ -3542,30 +3545,59 @@ gboolean GtkSalFrame::signalScroll( GtkWidget*, GdkEvent* pEvent, gpointer frame
     GdkEventScroll* pSEvent = reinterpret_cast<GdkEventScroll*>(pEvent);
 
 #if GTK_CHECK_VERSION(3,0,0)
-    //TODO: do something less feeble here
-    if (pSEvent->direction == GDK_SCROLL_SMOOTH)
+    // gnome#726878 check for duplicate legacy scroll event
+    if (pSEvent->direction != GDK_SCROLL_SMOOTH &&
+        pThis->m_nLastScrollEventTime == pSEvent->time)
+    {
         return true;
+    }
 #endif
 
-    static sal_uLong        nLines = 0;
-    if( ! nLines )
+    SalWheelMouseEvent aEvent;
+
+    aEvent.mnTime = pSEvent->time;
+    aEvent.mnX = (sal_uLong)pSEvent->x;
+    aEvent.mnY = (sal_uLong)pSEvent->y;
+    aEvent.mnCode = GetMouseModCode( pSEvent->state );
+    aEvent.mnScrollLines = 3;
+
+    switch (pSEvent->direction)
     {
-        char* pEnv = getenv( "SAL_WHEELLINES" );
-        nLines = pEnv ? atoi( pEnv ) : 3;
-        if( nLines > 10 )
-            nLines = SAL_WHEELMOUSE_EVENT_PAGESCROLL;
-    }
+#if GTK_CHECK_VERSION(3,0,0)
+        case GDK_SCROLL_SMOOTH:
+        {
+            double delta_x, delta_y;
+            gdk_event_get_scroll_deltas(pEvent, &delta_x, &delta_y);
+            //pick the bigger one I guess
+            aEvent.mbHorz = fabs(delta_x) > fabs(delta_y);
+            if (aEvent.mbHorz)
+                aEvent.mnDelta = -delta_x;
+            else
+                aEvent.mnDelta = -delta_y;
+            aEvent.mnScrollLines = 1;
+            pThis->m_nLastScrollEventTime = pSEvent->time;
+            break;
+        }
+#endif
+        case GDK_SCROLL_UP:
+            aEvent.mnDelta = 120;
+            aEvent.mbHorz = false;
+            break;
+        case GDK_SCROLL_DOWN:
+            aEvent.mnDelta = -120;
+            aEvent.mbHorz = false;
+            break;
+        case GDK_SCROLL_LEFT:
+            aEvent.mbHorz = true;
+            aEvent.mnDelta = 120;
+            break;
+        case GDK_SCROLL_RIGHT:
+            aEvent.mnDelta = -120;
+            aEvent.mbHorz = true;
+            break;
+    };
 
-    bool bNeg = (pSEvent->direction == GDK_SCROLL_DOWN || pSEvent->direction == GDK_SCROLL_RIGHT );
-    SalWheelMouseEvent aEvent;
-    aEvent.mnTime           = pSEvent->time;
-    aEvent.mnX              = (sal_uLong)pSEvent->x;
-    aEvent.mnY              = (sal_uLong)pSEvent->y;
-    aEvent.mnDelta          = bNeg ? -120 : 120;
-    aEvent.mnNotchDelta     = bNeg ? -1 : 1;
-    aEvent.mnScrollLines    = nLines;
-    aEvent.mnCode           = GetMouseModCode( pSEvent->state );
-    aEvent.mbHorz           = (pSEvent->direction == GDK_SCROLL_LEFT || pSEvent->direction == GDK_SCROLL_RIGHT);
+    aEvent.mnNotchDelta     = aEvent.mnDelta < 0 ? -1 : 1;
 
     // --- RTL --- (mirror mouse pos)
     if( AllSettings::GetLayoutRTL() )
-- 
2.5.0